we have the chief correspondent and jim, what are you hearing at pentagon? >> u.s. intelligence officials knew it was coming although they didn't know the exact timing. this one set off alarm bells, particularly because of the size of the blast. we are not relying on cl ing oi here. they said it was somewhere about 6 or 7 kilotons that could make it from to six times more powerful than a previous weapon. they did claim they did this with a much smaller warhead which would indicate perhaps it's making progress that could be put on the top of a missile that could be launched against the u.s. quite frankly that's impossible to prove. within minutes it seemed after the blast was reported, the white house responded and president obama called it a highly provocative act that undermines stability and threatens u.s. national security and the president said it demands swift and credible action by the international community, but everything comes to a halt. north korea is sanctioned out at this point and unless china decides to cutoff oil supplies and other goods to north kor